Electric heater.



E. N. LIGHTFOOT.

ELECTRIC HEATER.

APPLICATION FILED FEB. 6. 193.

Patnted 00c. 10,191

2 SHEETS-SHEET 1.

min/5885s IIWEIVTOR 4* 4 E. N. LIGHTFOOL EtECTRlC HEATER.

AEPLICATION FILED FEB. 6. I913 no 1 H Ow 1 M I S t W m u 7 m w t 2 9 R Z0 w J 7 Z am 3 ml" P W WIT/VESSg) ATTORNEY tudinal sec nal' elevation tI UNITED STATES PATENT orrion.

nnwm nrrenrroor, or NEW YORK; NY.

ELECTRIC HEATER.

Specification of Letters Patent.

To all whom it 912 my concern Be it known that I, EDWIN N. LIGHTFOOT, acitizen of the United States, residing at New York, in the county of NewYork and State of New York, have invented new and useful ImprovementsinElectric Heaters, of which the following is a full, clear, concise, andexact description, reference being had to the accompanying drawing,forming a art of this specification.

y invention relates to improvements in electric heaters.

One object of the invention is to provide a heater having two heatingplates heated by a common group of heating units arranged between thesame, said plates being held together by means-located between theheating units, w hereby said plates are maintained in proper spacedrelation at all times regardless of expansion and contraction.

Another object of the invention is to provide a novel construction of atwo plate heater employing a plurality of heating units, said. latesbeing held .together independently of said units whereby the latter maybe removed from the heater if it be comes necessary to replace adefective unit.

An additional object of the'invention is to provide an;improved'electric table stove which shall be neat, ornamental andcompact, having removable interfitting parts which may be assembled invarious difierent ways to perform a variety of functions.

In the accompanying drawings 1 have illustrated several embodiments ofthe invention. -Various other forms may be devised however which fallwithin the scope of the invention.

Figure 1 is a top plan view of the heating element of an electric stove,with one of the heating plates removed. Fig. 2 is a longiereof. Fig. 3is a transverse sectional elevation thereof. Fig. 4 is a side elevation,partly in section of the assembled stove. Fig. 5is a side elevation ofcertain parts of the' stove assembledin a difierent way. Fig; 6 is anend view on an enlarged scale of the handle of the heater element of thestove.

lan view of a modified form of heater. ig. 8 is a sectional elevationthereof. Figs.

9 10, 11, 12, 13 and 14 are sectional elevations of further modifiedforms'of heaters.

The preferred form of electric stove which is shown assembled in Fig. 4comprises a formed preferably from a 1 suitable stand '1 plates resistor'lto an adjacent resistor total resistance of the lower resistors,

single piece of sheet metal, and provided with legs 2, said legsconsisting of angle sections preferably welded or riveted to theupwardly turned flange 3 of the base.

'The base supports a pan 4, thelatter havmg a handle 5 and having anupper enlargement 6 forming-a shoulder. Said shoulder is adapted tosupport the heating element or heater, the latter comprising a bottomplate 7- having a vertical flange 8 and a top plate 9 having a verticalflange 10, said and having their flanges integrally united to form awater tight construction. Said heater has also a handle 11 within'whichthe oil:- cuit terminals are located, said handle being hereinafterdescribed more fully.

A sheet metal cover 12 having a downwardly extending flange 13 is alsoprovided said cover having a handle 14:. A broiling and toasting screen15 is shown in Fig.4 arranged within plate 16 is shown in Fig. 5 restingdirectly on the heater to provide a suitable heating surface for griddlecakes and the like. In Fig. 5 the pan has been removed, the electricheater resting directly The heating units, by which the twoheatingplates 7 and 9 are heated, each have in the preferred forma sheet metalchannel 17 on the bottom of which a strip of mica 18 Patented Oct.10,1916.

Application filed February 6, 1913. Serial No. 746,586. 7

fitting together as shown in Fig. 3,

the pan and an aluminum on the stand 1.

is placed. A slottedf resistance ribbon or 19 of less width than themica 18 then placed over said mica and a second sheet of mica 20 laidthereon; A second resistor-21 is superimposed on theimica' 20 and anadditional str p .of niica- 22 placed thereover. A strip of metalorflcover plate -23is placedover said mica 22 .andthe sheet met'alflanges of the flexible channel 17 y l are bentfover to firmly compressthe layers of 'micaan'd resistance ribbon andhold these elements inplace;

closev proximity .to the metal walls of'the channel thereby establishinggood heat conductinglrelations between the two.

The resistors are thus in l loo - The upper 'resistor in each unit iscon nected at its opposite. ends whereby all four resistors areconnectedin series. In

as shown in Figa similar mannerall of the lower resistors I Thetotal-resistance different from the and said resistors being'indepcndentgof each are connected in series. of the upper resistors 1sother; it is possible to obtain two hcat's by using one or the other. Byconnecting both .resistors is effected as shown in Fig. 2 by 'U shapedmetallic strips"-24land' 25 said strips' -being, suitably insulated .bymica. The ends of two of the resistors are of reduced width and arefolded over to'form a pair'of terminals 26 for the upper set ofresistors. A similar pair of terminals 27 is provided for the lowerresistors asshown inFig.1'."

The heating plates/7 and 9 are spaced apart by metallic bars or strips28. as shown in Fig. Said latesare'integrally'united to said bars preerably by electric-welding. 7

- closure slightly different from the preceding Accordingly they arespaced apart the proper distance to permit the'heatmg units to, belocated between said plates-and the proper spacing is maintainedirrespective of distortion due to expansion and contrac tion.Accordingly the walls of the channel are always in close proximity tothe heating plates and a good thermal conducting re lation ismaintained. The bottom of each channel maybe electrically-welded to theadjacent heating plate "if .desired- With such aconstruction the thermalconductivity. is ver good. The. heating-anits'are not re mova le.infsuch a case ho ever and hence under some circumstances it isdesirable not to weld-said units. but to leave them unattachedwherebythey may be slipped in and out from, between the heating plates toprovide-for occasional renewals.

It will be seen that either heating plate mayjbe used .as' the uppersurface of the heater by simply, inverting the latter. The flangesfornra pan-whereby the heater may be used as a frying. and for similar 1purposes. The flat base may be used for griddle cakes or the like,though I'prefer to. use an aluminum"'plate in addition as shown in Fig.5. With the arrangementshown in Fig. the stove may be usedfor broilingpurposes, the meat being laced on thescreen 15, the cover -12 providingan air spaceabove the upper surface :of the heater, thereby minimizingloss of heat in an upwardly direction. The stove may also be used forheating water, cofice, etc.,- by simple'restin the vessel thereon. "Itmay also be-used or'a great many other kinds of cooking and for variouspurposes which will readily suggest themselves.

The circuit connections are made within the handle 11 said handle havingan internal sheet metal tubular member 29 the outer end of which is.provided with a second metallic tube 30 in'position within th'ehandle.

aid tube a'sfshown in Fig. 6-is provided with a slotBlwhich guides theplugmember of the separable connector (not shown). 'Thecircuit terminalpins 32 are carried by the head 33 and are electrically connected to theterminal extensions 26, 27 previously deinclosures, each heating unitbeing provided with a pair of terminals 39, 4O ,tvhereby .each. unitconstitutes an independent heater. i r A The construction in Fig. 9 isquite similar to that just described except that the heating plates areWelded together at their edges thereby forming a watertight ininclosure.

The construction Fig. 10 is similar to the preceding figures except thatthe spacers 37 are of'varying widths, the middle spacer being wider thanthe other two. This provides for a more uniform distribution of heat.The middle spacer may be provided with an-opening 39 if desiredto'permit' the upward circulation of liquid therethrough.

In Figs. 11 and 12 the heating plates are spaced apart by spacers 40 ofgreater thickness than the thickness of the heating units. Said spacersmay assume many different forms, a number of modifications beingillustrated. The spacers in Fig. 12 are hollow and provided withopenings therethroughregistering with corresponding openings intheheating plates to facilitate circulation. F igl 13 is somewhatsimilar to the above figures and will be readily understood.

In Fig. 14: the heating units are removable and are held in closeproximity to the u per and lower heating plates by T shape retainersintegrally united to said plates.-

The various forms of heaters described I may be used within oven wallsfor example and .are so designed that the individual units..

maybe replaced when necessary. They may w also be used in various otherrelations other than in ovens and table stoves.

equivalent means wherever such means fall within the'scope of theappended claims.

Having thus described my invention, what I claim as new and desire tosecure by LettersPatent of the United States is:

.1. An electric heater comprising a plu-v rality. of electric heaterunits spaced apart;

relatively thin metallic heat dissipating plates in contact withopposite sides of said units, and spacers of a thickness substan- 1units between united to one of them,

. plates are integrally the thickness of said units said 'units to whichsaid d so that said units are held in close thermal contact with both-ofsaid plates to provide a reversible heater having two heating surfaces.2'. An electric heater having heating surfaces of substantial'area onopposite sides thereof so that the heater is reversible, said heaterbeing provided with a pair of metal heat dissipating plates spacedapart, electric heating units-between said plates and integrally unitedto one of them and spacers between said units to which both of platesare united, the periphery of said plates being integrally un'ted to forma tia-lly equal to located between water-tight heater.

3. An electric heater having heating surfaces of substantial area onopposite sides thereof so that the heater is reversible, said heatercomprising apair of spaced, metal, heat dissipating plates, electricheating sa'd plates and integrally and spacers between said units towhich both of the plates; are united, said spacers being of a thicknesssubstantially equal to the thickness of the units, the edges of theplates being integrally united to form a water-tight heater.

4. A double surface electric heater comprising a pair .0 heatdissipating meta plates, a plurality of substantially parallel heatingunits arranged between said plates and integrally united to one of them,a plurality of substantially parallel metal ele; ments. arranged betweensaid heating units and of a thickness substantially equal to the a bothof said plates metal eleis held-in said plates thickness of said units,being integrally united to said ments whereby the other plate closecontact with said units,

"having flanged peripheries, one of which fits within the other, saidflanges being integrally united to form a water-tight joint.

5. Ina electrical heater, in combination, a .plurality oi substantiallyparallel, spaced apart, heating units, each unit comprising a sheetmetal resistance carrier consisting a resistance inclosed within saidchannel an insulated therefrom, a plurality of shbstantially parallelmetal bars arrangedlin the spaces between said un'ts and a pair of heatdissipatingplates arranged on opposite sides of said units, one of saidplates being integrally united to one surface of each resistance carrierand both plates being inteally united to said bars, whereby the otherlate is also held in close heat conducting relation with the oppositesurface of said units.

6. In an electric heater in combination, a.

' weldable, metallic,

ing their peripheries welded substantially parallel hea ing plurality ofunits space from each other, a plurality of substantially parallel metalchannels arranged between sai heatingunits, and of a thicknesssubstantially equal to the thickness ofsai units, and a pair of metallicplates on' opposite sides of said heating units, said plates beingelectrically welded to said channels, said channels being slightlycompressible whereby said plates may be ressed into close contact withsaid units, regardless of slight initial variations in the thicknessthereof. 1

7 A double surface electric heater having a pair of parallel weldable'metallic heat dissipating plates and metallicspacers located betweensaid plates for holding the same in spaced relation, said spacers beingwelded to said plates and mechanically inheater units located betweensai heating plates and between said spacers,

said units having their casings welded'to one of said heating plates.

8. An electric heater having a pair of heat dissipating plates arrangedparallel to each other, spacers located between said plates for holdingthe same in spaced relation, and a heater unit located between saidplates and between sai said heater unit having a resistor a resistancecarrier incasing said resistor, said resistance carrier consisting oweldable sheet metal and being welded to one ofthe aforesaid heatdissipating plates.

9. A flat electric heater plate having two is reversible, said platecomprising a plurality of electric heater units, a plurality of spacersbetween the edges 0 said units,

weldable metallic heat dissipating plates on each side of said units,said plates havform a water-tight inclosure and being wel -ed to saidspacers to'hold said heater units in close thermal contact with the heatdissipating 10.

plates. A n electric heater having two opposite heating surfaces so thatthe heater is reversible, said heater comprising two relatively thinmetallic heat dissipating plates spaced apart and integrally united attheir edges to form a wate -tight inclosure andmetallically incasedelectric heater units between sai plates, said units having theircasings integrally united to said plates.

In witness whereof, I have hereunto subscribed my name in the presenceof two witnesses. EDWIN N. LIGH'IYFOOT.

Witnesses:

G110. B. Jones,

G. P. BROCKWAY.

' opposite heating surfaces so that the plate 1 p together toCorrections in Letters Patent No. 1,200,630.

I It is hereby certified that in Letters Patent No. 1,200,630, grantedOctober 10,

1916, upon the application of Edwin N. Lightfoot, of New York, N. Y.,for an improvement in Electric Heaters, errors appear in the printedspecification requiring correction es follo weq Page 3, line 45, claim5, for the words In a. electrical hee-ter read In an electricheater,""ee1ne page, line 81, claim 7, for the word mechanically readmetallicall'y; and that the eaid Letters Patent shouh i'be read withthese corrections therein that the same may conform to the record of thecase in the Patent Office Signed and sealed this 21st day of November,A. 1)., 19 16.

F. W. 1 1. CLAY;

[SEAL] Acting Gammissz'oner of Patents.

